The sillon alpin (‘Alpine furrow’) is a dramatic cleft in the French Alps, a river valley amid a landscape of jutting peaks. Which makes for a stunning cycle route – without the climbing you’d expect.
Half traffic-free, half on minor lanes, this route is cleverly pieced together at the narrow base of the Isère valley. The need to stay away from busy roads in such a contested space means more twists and turns than usual, so you’ll need to keep your navigational wits about you. Fortunately, the route is well signposted with clear V63 signs.
Presuming that you’d rather ride downhill (because why wouldn’t you), the Alpine resort of Aix les Bains is the start of the route. A glorious waterside promenade gives you views over Lac du Bourget; these first few kilometres are worth the entrance price on their own.
It remains largely traffic-free through the city of Chambéry before disgorging you onto ridiculously picturesque lanes, so chocolate-box perfect that you’ll be riding with a massive smile on your face. Vineyards carpet the valley floor, trees surround the valley slopes, and snow caps the mountains.
So it continues downriver to Grenoble, the self-styled Capital of the Alps with cable cars overhead, trams on the ground, and happily, bikes everywhere. The cycle route claims the riverbank as its own for a full 50km, blissfully ignoring the busy roads crammed into the valley floor. But do venture away from the river for a while to explore the city: it would make a good overnight stop.
The riverside track continues out of the city, with only the low growl of the ever-present autoroute to disturb the peace. Yet you soon learn to filter this out and cast your attention to the Isère on the other side.
The cycleway ends before Vinay. Here the route diverts onto sometimes hilly lanes through walnut groves, with a few sharp climbs up from the river. The bridges at Beauvoir and La Sône provide good views, though you could consider staying on the north bank and following the tiny road (Route du Mandret) between the two, which is arguably more scenic than the official route.
Returning to the riverbank at Romans-sur-Isère, it’s a gentle downhill canter once more on the wooded riverside cycleway to Valence and the River Rhône.
At 200km (120 miles) this is a leisurely three-day ride, or two days for the sporty. The twists and turns, as well as the busy cycleways, militate against taking it too fast.
For an Alpine route, pretty easy – because it stays on the valley floor. There are one or two short climbs up from the river in the lower reaches. The slog up to Vinay is probably the hardest, but suffice it to say that every time you cross the river, that means a climb is coming. Still, the route should be well within the ability of most cyclists.
The route’s almost entirely paved, so any bike will do. You’ll see a lot of road bikes on the lanes around here.
Yes: the route is excellently signposted with V63 signs.
The V63 has a sister route, the V62. This begins in the hills above Annecy and will descend to meet the V63 near Chambéry. Every bit as scenic, it’s only half complete thus far. You could consider finding your own way past the missing sections, but the roads are busy and fairly hilly.
At its downstream end, the route meets the Via Rhona, aka EuroVelo 17 – the cycleway along the River Rhône. Combining the two makes for a magnificent 500km (310-mile) circuit via Belley, Lyon and Tournon-sur-Rhône.
A railway line runs the full length of the route, with frequent TER Auvergne-Rhône-Alpes services which carry bikes without reservation.